CN110931758B - Sulfur composite material for lithium-sulfur battery and preparation method thereof - Google Patents

Sulfur composite material for lithium-sulfur battery and preparation method thereof Download PDF

Info

Publication number
CN110931758B
CN110931758B CN201911311478.5A CN201911311478A CN110931758B CN 110931758 B CN110931758 B CN 110931758B CN 201911311478 A CN201911311478 A CN 201911311478A CN 110931758 B CN110931758 B CN 110931758B
Authority
CN
China
Prior art keywords
sulfur
lithium
composite material
nano
hours
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201911311478.5A
Other languages
Chinese (zh)
Other versions
CN110931758A (en
Inventor
弓胜民
张立
赵尚骞
杨容
赵春荣
孙浩博
朱秀龙
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Automotive Battery Research Institute Co Ltd
Original Assignee
China Automotive Battery Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China Automotive Battery Research Institute Co Ltd filed Critical China Automotive Battery Research Institute Co Ltd
Priority to CN201911311478.5A priority Critical patent/CN110931758B/en
Publication of CN110931758A publication Critical patent/CN110931758A/en
Application granted granted Critical
Publication of CN110931758B publication Critical patent/CN110931758B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention relates to a sulfur composite material for a lithium-sulfur battery and a preparation method thereof. According to the invention, the multi-dimensional carrier is constructed by the nano materials with different micro-morphology structures, so that the content of active substance sulfur in the composite material can be obviously improved, a good electronic conductive network is formed by the bridging action of the high-conductivity nano particles and the chemical adsorption action of the high-conductivity nano particles on polysulfide, and the charge-discharge cycle performance of the lithium-sulfur battery is improved. The sulfur content of the multi-dimensional sulfur composite material prepared by the method can reach more than 90 percent, and the initial discharge specific capacity of the composite material can reach 1290 mAh/g.

Description

Sulfur composite material for lithium-sulfur battery and preparation method thereof
Technical Field
The invention relates to the field of electrochemistry, in particular to a sulfur composite material for a lithium-sulfur battery and a preparation method thereof.
Background
With the rapid development in the fields of electric vehicles, energy storage equipment and the like, the requirements on the energy density and the cycle performance of the battery are more urgent. The lithium secondary battery plays a vital role in important strategic fields of electric vehicles, electric tools, smart grids, distributed energy systems, national defense and the like. The lithium ion battery has the advantages of long cycle life, small self-discharge, environmental friendliness and the like as a secondary battery system with the best comprehensive performance at present. However, after more than twenty years of development, the lithium ion battery has basically reached its theoretical energy density limit, and its development space is very limited, so that it is urgently needed to develop a new secondary battery system with higher capacity, and it has become a necessary direction for the development of secondary battery industry to construct a new lithium secondary battery system to obtain higher energy density.
Lithium sulfur secondary batteries have theoretical capacity as high as 2600Wh/kg, are far greater than commercial secondary batteries used at present, and have received increasing acceptance and attention from the research and development fields and the industrial circles due to abundant elemental sulfur reserves, low price and environmental friendliness. However, lithium sulfur batteries still have a series of problems that prevent their commercial application. First, elemental sulfur and sulfides are inherently poor conductors of electrons. The electronic conductivity of elemental sulfur at room temperature is 5 x 10-30S/cm, more conductive agent needs to be added in practical application, thereby reducing the specific energy of the whole battery. Secondly, elemental sulfur is used as an electrode active material, lithium polysulfide serving as a discharge intermediate product of the elemental sulfur is easy to dissolve and diffuse in organic electrolyte, so that part of active substances are lost, the viscosity of the electrolyte is increased, the ionic conductivity is reduced, and the lithium polysulfide shuttles back and forth between a positive electrode and a negative electrode, so that the coulombic efficiency is low, and part of the lithium polysulfide directly reacts with a lithium negative electrode to cause self-discharge of the battery. These problems caused by lithium polysulfides all result in poor cycling performance of the battery and low utilization of the active material. In addition, the volume of the elemental sulfur and the discharge product thereof also follows expansion and contraction (75%) in charge and discharge cycles, and after a certain number of cycles, the electrode structure collapses and the electrode fails (Z.W.Seh, Y.M.Sun, Q.F.Zhang, Y.Cui.chem.Soc.Rev.45(2016) 5605). Therefore, the research on improving the conductivity of the sulfur electrode, preventing the dissolution and diffusion of intermediate products in the charging and discharging process, preventing the collapse failure of the electrode structure and improving the cycle performance is the key point of the lithium-sulfur battery.
In order to improve the cycle performance of the lithium-sulfur battery, a common solution is to add a conductive agent and a material with adsorption capacity to compound with sulfur so as to solve the problem of conductivity and the problem of polysulfide dissolution. Such as various carbon materials (graphene, porous carbon, carbon nanotubes), polymers, metals and their oxides, and the like. TiO 22These materials have strong chemisorption to polysulfides, but most metal oxides are less conductive than carbon materials, ultimately hindering electron transportThe approach is not beneficial to the exertion of the capacity of the lithium battery (X.Liu, J.Q.Huang, Q.Zhang, L.Q.Mai, adv.Mater.2017,29,1601759). In contrast, titanium nitride (TiN) nanoparticles are a more promising matrix material with good electrical conductivity (4000-. TiN is a novel matrix material, and the high capacity and excellent rate performance of TiN are not only due to the strong bonding with S, N atoms, but also due to the polar character of TiN. Based on the strong chemical adsorption effect of TiN on polysulfide and high conductivity of the polysulfide, the structural design of a high-performance lithium-sulfur battery can be realized, and the composite material compounded with sulfur has higher charge and discharge performance (the initial discharge specific capacity can reach over 1200 mAh/g). However, the high sulfur loading characteristics of the electrodes are not the only condition to obtain a high energy density Li-S battery. To improve the energy density of the lithium-sulfur battery, not only higher specific capacity of active materials and higher sulfur load are required, but also the proportion of inactive materials in the composition of each part of the battery needs to be reduced as much as possible. For this purpose, it is necessary to design a cathode material having a higher sulfur content. However, in the past reports, the sulfur content of the positive electrode composite material was generally 80% or less (Lu D, Li Q, Liu J, Zheng J, Wang Y, Ferrara S, Xiao J, Zhang JG, Liu J. ACS Appl Mater interfaces.2018; 10(27): 23094.).
Disclosure of Invention
Aiming at the defects and shortcomings in the prior art, the invention provides a sulfur composite material for a lithium-sulfur battery and a preparation method thereof.
One of the purposes of the invention is to provide a sulfur composite material for a lithium sulfur battery, which comprises a carrier and an active substance loaded on the surface of the carrier, wherein the active substance is sulfur, and the carrier is composed of a nanoparticle material, a linear nanomaterial and a layered nanomaterial. In the invention, the multi-dimensional sulfur carrier is constructed by the nano materials with different microstructures, so that the content of active substance sulfur in the composite material can be obviously improved, a good electronic conductive network is formed through the bridging action of the high-conductivity nano particles, and the charge-discharge cycle performance of the lithium-sulfur battery can be improved through the chemical adsorption action on polysulfide. The sulfur content of the sulfur composite material prepared by the method can reach more than 90 percent, and the initial discharge specific capacity of the composite material can reach 1290 mAh/g.
According to some preferred embodiments of the invention, the sulfur composite has a point-line-plane multi-dimensional microstructure; and/or the nanoparticle material is one or more of alumina, iron oxide, copper oxide, titania, silica, tin oxide, zirconia, and titanium nitride; the linear nano material is a carbon nano tube or a carbon fiber; the layered nano material is graphene or graphene oxide. In the invention, the multi-dimensional microstructure refers to a composite structure material formed by combining nano materials with different dimensions, such as a zero-dimension nano particle material, a one-dimensional linear nano material, a two-dimensional layered nano material and the like.
According to some preferred embodiments of the present invention, the sulfur content is 70 to 99 parts by weight, the nanoparticle material content is 1 to 30 parts by weight, the nano linear material content is 1 to 30 parts by weight, the nano sheet material content is 1 to 30 parts by weight, preferably, the sulfur content is 80 to 95 parts by weight, the nanoparticle material content is 1 to 20 parts by weight, the nano linear material content is 2 to 20 parts by weight, and the layered nano material content is 2 to 20 parts by weight.
In another aspect, the present invention provides a method for preparing the sulfur composite material, comprising the steps of:
step 1), dispersing nano sulfur powder or nano sulfur prepared by in-situ reduction in a solvent to prepare nano sulfur dispersion liquid;
step 2), mixing and dispersing the nano-particle material, the linear nano-material and the layered nano-material in proportion to obtain a carrier nano-material mixture;
step 3), mixing the nano sulfur dispersion liquid and the carrier nano material mixture according to a proportion to obtain a pre-loaded composite material;
and 4) heating the pre-loaded composite material under vacuum to obtain the composite material.
In the invention, the nano-sulfur dispersion liquid is prepared by chemical in-situ reduction or physical dispersion; mixing the nano materials forming the microscopic multidimensional structure carrier in proportion to realize the construction of a point-line-surface conductive network structure; mixing a nano sulfur material and a carrier nano material mixture to realize the primary loading of sulfur on a multi-dimensional structure carrier; and (3) carrying out high-temperature treatment on the pre-loaded composite material under vacuum to realize uniform loading of sulfur on the multi-dimensional structure carrier. The invention provides a high-performance high-sulfur-content sulfur cathode composite material, and provides conditions for realizing a high-energy-density lithium-sulfur battery. The composite material has a multi-dimensional microstructure of point-line-surface, high sulfur content, good adsorption effect on polysulfide and good conductivity.
According to some preferred embodiments of the present invention, in step 1), the in-situ reduction is dropping a formic acid solution into a sodium thiosulfate solution to form the nano sulfur dispersion; and/or the temperature of the nano sulfur dispersion liquid is 10-90 ℃, preferably 30-80 ℃; and/or the concentration of the nano sulfur dispersion liquid is 10-50 g/L.
According to some preferred embodiments of the present invention, in the step 1), the dispersion is stirring dispersion and/or ultrasonic dispersion for 10-24 hours; the solvent is a polar solvent or a non-polar solvent, and is preferably water, an alcohol solvent, acetone, carbon tetrachloride or tetrahydrofuran; and/or in the step 1), a dispersing agent is further added into the solvent, the dispersing agent is an ionic or nonionic surfactant, the adding amount of the dispersing agent is 1-10 wt%, and preferably, the dispersing agent is selected from one or more of sulfonate, quaternary ammonium salt, an ester compound, a polyoxyethylene compound and polyvinylpyrrolidone.
According to some preferred embodiments of the present invention, in the step 2), the mass ratio of the nanoparticle material, the nano linear material and the nano sheet material is (1-30): 1-30, preferably (1-9): 1-9; in the step 2), the temperature is controlled to be 30-80 ℃, and the stirring time is 12-48 h. In the invention, when the three morphologies of the nano material are mixed to construct the multi-dimensional structure, the nano material can be dispersed by powder materials, nano material slurry and the like, and the uniform dispersion liquid can be prepared by adding different nano materials into a solvent in proportion and performing ultrasonic dispersion or mechanical stirring at a certain temperature.
According to some preferred embodiments of the invention, in the step 3), the nano sulfur dispersion is slowly added to the carrier nano material mixture under mechanical stirring or ultrasonic stirring, preferably for 2-10 hours, and then stirred at 30-80 ℃, preferably 40-80 ℃, for 12-48 hours, and then vacuum-filtered, washed, and dried under vacuum to obtain the nano sulfur composite material. In the invention, in order to ensure that the nano sulfur and the carrier material are uniformly mixed, the reactor is provided with a stirring and dispersing device, such as one or two of mechanical stirring and dispersing, ultrasonic dispersing and the like.
According to some preferred embodiments of the present invention, in the step 4), the heating temperature of the heating treatment is 120 to 200 ℃ and the heating time is 5 to 20 hours. The invention compounds sulfur on the multi-dimensional nanometer material carrier through the melting process of sulfur.
In still another aspect, the present invention provides a use of the sulfur composite material in a lithium-sulfur battery; preferably, the lithium-sulfur battery comprises a positive electrode, a negative electrode and an electrolyte, the sulfur composite material is used as the positive electrode, the negative electrode is selected from one or more of metallic lithium, lithium alloy, lithium-doped carbon, lithium-doped silicon and lithium-doped graphite, and the electrolyte is selected from one or more of liquid electrolyte, colloidal polymer electrolyte and solid electrolyte.
Compared with the prior art, the invention not only considers the problems of poor conductivity of elemental sulfur, dissolution loss of polysulfide and the like, but also fully utilizes a three-dimensional conductive network formed by a plurality of nano materials in a dot-line-plane form and sufficient micropore space in a composite structure, effectively relieves the structural collapse of the sulfur electrode caused by volume expansion in the charging and discharging process, and the composite of the nano structure can provide sufficient electrochemical reaction area, and effectively improves the stability of the sulfur electrode. The sulfur composite material prepared by the invention has higher sulfur content, higher specific discharge capacity, good cycle performance and high-current discharge rate performance, and can be used as a positive electrode material of a high-performance secondary lithium-sulfur battery.
The invention has the beneficial effects that: 1) the special point-line-surface microstructure can effectively restrain polysulfide ions in the electrode, so that active substances react in a certain area, and the diffusion loss of polysulfide is inhibited, thereby improving the utilization rate of the active substances and the electrochemical cycle performance. 2) The nano-particle titanium nitride in the composite material has excellent electronic conductivity, a good electronic conductive network can be constructed in the composite material, the rate capability in the charging and discharging process is improved, the transformation of polysulfide in electrochemical reaction has a catalytic effect, the reaction rate is promoted, and the specific capacity and the cycle performance of the battery are improved. 3) The composite material with the nano structure provides a good electrochemical reaction interface, and the special point-line-surface spatial structure can effectively relieve the stress change caused by density change in the charging and discharging processes of the sulfur electrode, relieve the volume effect, solve the problem of unstable structure of the sulfur electrode in the charging and discharging processes, improve the specific capacity, the power performance, the cycle life and the like of the battery.
Drawings
FIG. 1 is a schematic illustration of the preparation of a sulfur composite of the present invention;
FIG. 2 is a graph of the thermal weight loss of the sulfur composite of example 3;
FIG. 3 is a first charge-discharge specific capacity curve diagram of the sulfur composite material of the present invention;
FIG. 4 is a graph of the cycle profile of the sulfur composite of the present invention;
FIG. 5 is a graph of the AC impedance of the sulfur composite of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. The technical solution of the present invention is not limited to the following specific embodiments, and includes any combination of the specific embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.
In the present invention, the specific techniques or conditions not specified in the examples are performed according to the techniques or conditions described in the literature in the art or according to the product specification. The instruments and the like are conventional products which are purchased by normal distributors and are not indicated by manufacturers. The chemical raw materials used in the invention can be conveniently bought in domestic chemical product markets.
Example 1
This example provides a method for preparing a sulfur composite material, as shown in fig. 1, which is a schematic view of the preparation of the sulfur composite material in this example, and includes the following steps:
1)100mL of deionized water was added with 5g of polyvinylpyrrolidone, and stirred at 50 ℃ for 2 hours to prepare a homogeneous solution. 2g of nano sulfur (20nm) was added to the above solution, dispersed with ultrasound at 50 ℃ for 2h, and then stirred for 12 h.
2) Adding 0.2g of graphene into 50mL of ethanol, and performing ultrasonic dispersion for 2 hours; adding 0.2g of carbon nano tube into 50mL of ethanol, and carrying out ultrasonic dispersion for 2 h; 0.1g of titanium dioxide (20nm) was added to 50mL of ethanol and ultrasonically dispersed for 2 hours. Adding the titanium dioxide dispersion liquid into the carbon nano tube dispersion liquid under stirring, and stirring for 5 hours at the temperature of 30 ℃; and then adding the graphene dispersion liquid into the mixed liquid, and continuously stirring for 12 hours to prepare the nano material dispersion liquid.
3) Slowly adding the nano-sulfur dispersion liquid in the step 1) into the nano-material dispersion liquid in the step 2) under mechanical stirring for 5 hours, and then keeping stirring the mixed liquid at 60 ℃ for 20 hours. The mixture was vacuum filtered and washed 3 times with deionized water. The resulting solid was dried under vacuum at 55 ℃ for 24 h.
4) Heating the composite material obtained in the step 3) to 180 ℃ under vacuum, and keeping the temperature for 5 hours. And cooling to room temperature, and crushing the black solid to obtain the sulfur composite material.
The sulfur content of the obtained sulfur composite material is 82.8 percent through tests.
Example 2
This example provides a method of preparing a sulfur composite, comprising the steps of:
1)100mL of deionized water was added with 3g of polyvinylpyrrolidone, and stirred at 50 ℃ for 2 hours to prepare a homogeneous solution. 12g of sodium thiosulfate was added to the above solution, and then 100mL of a 2M formic acid solution was slowly added dropwise with stirring, followed by treatment with stirring for 10 hours. Preparing the nano sulfur dispersion liquid.
2) Adding 0.2g of graphene into 50mL of deionized water, and carrying out ultrasonic dispersion for 2 h; adding 0.2g of carbon nano tube into 50mL of deionized water, and carrying out ultrasonic dispersion for 2 h; 0.1g of titanium nitride (20nm) was added to 50mL of deionized water and ultrasonically dispersed for 2 h. Adding the titanium nitride dispersion liquid into the carbon nano tube dispersion liquid under stirring, and stirring for 5 hours at the temperature of 30 ℃; and then adding the graphene dispersion liquid into the mixed liquid, and continuously stirring for 12 hours to prepare the nano material dispersion liquid.
3) Slowly adding the nano-sulfur dispersion liquid in the step 1) into the nano-material dispersion liquid in the step 2) under mechanical stirring for 4 hours, and then keeping stirring the mixed liquid at 60 ℃ for 20 hours. The mixture was vacuum filtered and washed 3 times with deionized water. The resulting solid was dried under vacuum at 55 ℃ for 24 h.
4) Heating the composite material obtained in the step 3) to 150 ℃ under vacuum, and keeping the temperature for 10 hours. And cooling to room temperature, and crushing the black solid to obtain the sulfur composite material.
The sulfur content of the obtained sulfur composite material is 85.5 percent through tests.
Example 3
This example provides a method of preparing a sulfur composite, comprising the steps of:
1)100mL of deionized water was added with 3g of polyvinylpyrrolidone, and stirred at 50 ℃ for 2 hours to prepare a homogeneous solution. 15g of sodium thiosulfate was added to the above solution, and then 120mL of a 2M formic acid solution was slowly added dropwise with stirring, followed by treatment with stirring for 10 hours. Preparing the nano sulfur dispersion liquid.
2) Adding 0.15g of graphene into 100mL of deionized water, and performing ultrasonic dispersion for 2 hours; adding 0.15g of carbon nano tube into 100mL of deionized water, and carrying out ultrasonic dispersion for 2 h; 0.3g of titanium nitride (20nm) was added to 100mL of deionized water and ultrasonically dispersed for 2 h. Adding the titanium nitride dispersion liquid into the carbon nano tube dispersion liquid under stirring, and stirring for 5 hours at the temperature of 30 ℃; and then adding the graphene dispersion liquid into the mixed liquid, and continuously stirring for 12 hours to prepare the nano material dispersion liquid.
3) Slowly adding the nano sulfur dispersion liquid in the step 1) into the nano material dispersion liquid in the step 2) under ultrasonic stirring for 6 hours, and then keeping the ultrasonic stirring of the mixed liquid at 50 ℃ for 40 hours. The mixture was vacuum filtered and washed 3 times with deionized water. The resulting solid was dried under vacuum at 55 ℃ for 24 h.
4) Heating the composite material obtained in the step 3) to 160 ℃ under vacuum, and keeping the temperature for 5 hours. And cooling to room temperature, and crushing the black solid to obtain the sulfur composite material.
Fig. 2 is a thermal weight loss curve chart of the sulfur composite material in this example, and the sulfur content in the obtained sulfur composite material is 90.8%.
Experimental example 1
The sulfur composite material prepared in examples 1, 2 and 3 was used as a positive electrode material, SP was used as a conductive agent, PVDF was used as a binder, NMP was used as a solvent to prepare a sulfur electrode, and the areal density of sulfur was 3.0mg/cm2And assembling the lithium-sulfur battery by using metal lithium as a negative electrode, Celgard2400 as a diaphragm and 1mol/L lithium bistrifluoromethylsulfonate imide (LiTFSI) +0.2mol/L lithium nitrate/ethylene glycol dimethyl ether (DME) +1, 3-Dioxolane (DOL) (volume ratio of 1:1) as an electrolyte.
The cell was discharged at a constant current with a current density of 0.1C (1C 1672mAh/g, calculated as sulfur) and a cut-off voltage of 1.7V to 2.6V. FIGS. 3 and 4 are initial charge-discharge curves and cycle curves for three sulfur composites of examples 1, 2, and 3, respectively: the first discharge specific capacity of elemental sulfur of the composite anode material in the embodiment 1 is 1214mAh/g, two obvious voltage platforms appear in a discharge curve, and the discharge specific capacity is kept at 985mAh/g after 100 cycles; in the embodiment 2, the first discharge specific capacity of elemental sulfur of the composite anode material is 1245mAh/g, two obvious voltage platforms appear in a discharge curve, and the discharge specific capacity is kept 1048mAh/g after 100 cycles; the first discharge specific capacity of the elemental sulfur of the composite cathode material in the embodiment 3 is 1290mAh/g, two obvious voltage platforms appear in a discharge curve, and the discharge specific capacity is kept at 1132mAh/g after 100 cycles; it is apparent from fig. 4 that the cycle performance of the sulfur composite material in example 3 is better than that of the other two materials, which shows that the TiN nanoparticles with high electron conductivity in the multi-dimensional space structure of the sulfur composite material play a role in bridging the nanomaterials with different structures and promoting the transformation of sulfur in the electrochemical reaction process. In addition, as can be shown from the ac impedance curves of the three sulfur composite materials in examples 1, 2, and 3 in fig. 5, the TiN nanoparticles with a proper proportion have a good electron conduction effect in the sulfur composite, effectively reduce the impedance among the components in the positive electrode material, and have a positive effect on improving the battery performance.
Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (2)

1. A method for preparing a sulfur composite material for a lithium-sulfur battery is characterized by comprising the following steps:
1) adding 3g of polyvinylpyrrolidone into 100mL of deionized water, and stirring at 50 ℃ for 2h to prepare a uniform solution; adding 15g of sodium thiosulfate into the solution, then slowly dropwise adding 120mL of 2M formic acid solution under stirring, and then stirring for 10 hours to prepare nano sulfur dispersion liquid;
2) adding 0.15g of graphene into 100mL of deionized water, and performing ultrasonic dispersion for 2 hours; adding 0.15g of carbon nano tube into 100mL of deionized water, and carrying out ultrasonic dispersion for 2 h; adding 0.3g of 20nm titanium nitride into 100mL of deionized water, and carrying out ultrasonic dispersion for 2 h; adding the titanium nitride dispersion liquid into the carbon nano tube dispersion liquid under stirring, and stirring for 5 hours at the temperature of 30 ℃ to obtain a mixed liquid; then adding the graphene dispersion liquid into the mixed liquid, and continuously stirring for 12 hours to prepare a nano material dispersion liquid;
3) slowly adding the nano sulfur dispersion liquid in the step 1) into the nano material dispersion liquid in the step 2) under ultrasonic stirring for 6 hours, and then keeping ultrasonic stirring of the mixed liquid at 50 ℃ for 40 hours; vacuum filtering the mixed solution, and washing for 3 times by using deionized water; drying the obtained solid at 55 ℃ for 24h under vacuum;
4) heating the composite material obtained in the step 3) to 160 ℃ under vacuum, and keeping for 5 hours; and cooling to room temperature, and crushing the black solid to obtain the sulfur composite material.
2. The method of claim 1, wherein the lithium-sulfur battery comprises a positive electrode, a negative electrode and an electrolyte, the sulfur composite is used as the positive electrode, the negative electrode is selected from one or more of metallic lithium, lithium alloy, lithium-doped carbon and lithium-doped silicon, and the electrolyte is selected from one or more of a liquid electrolyte, a colloidal polymer electrolyte and a solid electrolyte.
CN201911311478.5A 2019-12-18 2019-12-18 Sulfur composite material for lithium-sulfur battery and preparation method thereof Active CN110931758B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911311478.5A CN110931758B (en) 2019-12-18 2019-12-18 Sulfur composite material for lithium-sulfur battery and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911311478.5A CN110931758B (en) 2019-12-18 2019-12-18 Sulfur composite material for lithium-sulfur battery and preparation method thereof

Publications (2)

Publication Number Publication Date
CN110931758A CN110931758A (en) 2020-03-27
CN110931758B true CN110931758B (en) 2021-11-05

Family

ID=69864275

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911311478.5A Active CN110931758B (en) 2019-12-18 2019-12-18 Sulfur composite material for lithium-sulfur battery and preparation method thereof

Country Status (1)

Country Link
CN (1) CN110931758B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113451557B (en) * 2021-06-25 2022-04-15 安徽工业大学 Preparation method of lithium-sulfur battery positive-grade material

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104600265A (en) * 2015-01-06 2015-05-06 中国科学院化学研究所 High-performance carbon-sulfur composite anode material and preparation method thereof
CN108878847A (en) * 2018-07-03 2018-11-23 西南交通大学 Lithium sulfur battery anode material and preparation method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104362293B (en) * 2014-12-05 2017-05-17 上海空间电源研究所 Sulfur-containing positive electrode material with multi-grade structure as well as preparation method and application of sulfur-containing positive electrode material

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104600265A (en) * 2015-01-06 2015-05-06 中国科学院化学研究所 High-performance carbon-sulfur composite anode material and preparation method thereof
CN108878847A (en) * 2018-07-03 2018-11-23 西南交通大学 Lithium sulfur battery anode material and preparation method thereof

Also Published As

Publication number Publication date
CN110931758A (en) 2020-03-27

Similar Documents

Publication Publication Date Title
Li et al. Sphere-like SnO2/TiO2 composites as high-performance anodes for lithium ion batteries
CN107634207B (en) Silicon-inlaid redox graphene/graphite-phase carbon nitride composite material and preparation and application thereof
CN109921090B (en) Lithium ion all-solid-state full battery and preparation method thereof
CN103280571B (en) A kind of anode material for lithium-ion batteries and preparation method thereof
Hao et al. Electrospun single crystalline fork-like K2V8O21 as high-performance cathode materials for lithium-ion batteries
US20120315550A1 (en) Graphene-modified lithium iron phosphate positive electrode active material, preparation of the same and lithium-ion secondary cell
CN104157853B (en) A kind of negative material, its preparation method and application
CN112670516A (en) Three-dimensional composite current collector and preparation method thereof
CN108199014B (en) Porous nitrogen-doped carbon/Fe2O3Graphene foam flexible composite material, preparation method and application thereof
EP3319152A1 (en) Doped conductive oxide and improved electrochemical energy storage device polar plate based on same
CN108899499B (en) Sb/Sn phosphate-based negative electrode material, preparation method thereof and application thereof in sodium ion battery
Hao et al. Facile fabrication of Fe3O4 octahedra with bimodal conductive network of nanoporous Cu and graphene nanosheets for high-performance anode in Li-ion batteries
CN113644244B (en) Chromium oxide/carbon fluoride/highly conductive substance composite material for lithium primary battery
CN110931727A (en) Preparation method of conductive polymer-coated silicon-based negative electrode material
CN110931758B (en) Sulfur composite material for lithium-sulfur battery and preparation method thereof
CN111974430B (en) Preparation method of monoatomic copper catalyst and application of monoatomic copper catalyst in positive electrode of lithium-sulfur battery
Zhao et al. Cathode materials for aqueous zinc-ion batteries and prospect of self-supporting electrodes: A review
CN111313023B (en) High-solid-content semi-solid electrode, preparation method thereof and lithium slurry flow battery comprising electrode
CN103050692A (en) Preparation method of grapheme-lithium manganese silicate anode material
CN104900883A (en) Preparation method of electroconductive agent for electrode
CN105449294A (en) Battery
CN115440966B (en) Copper-modified carbon fluoride/niobium oxide composite positive electrode material and preparation method thereof
CN103208622A (en) Preparation method of silver-doped carbon-encapsulated lithium titanate composite negative electrode material
CN114373933B (en) Solid-state battery positive plate, preparation method thereof and solid-state battery
CN111825076B (en) Carbon nanotube/MnO 2 composite material of core-sheath nano cable structure and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant